An unauthorized user may fraudulently request access to a resource using the authorization information of an authorized user. To prevent unauthorized access, a resource security system may implement access rules to reject access requests having certain parameters that are indicative of fraud. However, in response to being denied access, the unauthorized user may change their method for making fraudulent access requests, thereby changing the parameters, in order to avoid rejection by the access rules. In addition, authorized users may also change their methods for making legitimate access requests over time. Consequently, the performance of the access rules may degrade over time, increasingly denying access to authorized users or increasingly granting access to unauthorized users. Accordingly, there is a need for improved systems and methods for securing access to resources.